Xylene isomerization

Patent metadata

Field	Value
Publication number	US-10099974-B2
Application number	US-201515536596-A
Country	US
Kind code	B2
Filing date	Dec 16, 2015
Priority date	Dec 17, 2014
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

A process for producing xylenes, in particular para-xylene that is less energy intensive than conventional processes is provided. In an embodiment the process comprises contacting a feed mixture in an isomerization zone with a catalyst at isomerization conditions and producing an isomerized product comprising a higher proportion of p-xylene than in the feed mixture, wherein the catalyst comprises an acidic sulfonated catalytic membrane. Xylene isomerization can also be coupled with a p-xylene extraction process, where the raffinate (p-xylene deprived stream) from the extraction process is fed to an isomerization reactor to produce p-xylene. In an embodiment, the process can comprise: a) providing a feed stream comprising a mixture of xylene isomers including p-xylene; b) extracting p-xylene from the feed stream using a separator to separate the feed stream into a p-xylene rich stream and a p-xylene deprived stream; and c) delivering the p-xylene deprived stream to an isomerization unit, the isomerization unit including an acidic sulfonated catalytic membrane, and using the isomerization unit to produce an isomerized product comprising a higher proportion of p-xylene than in the p-xylene deprived stream delivered to the isomerization unit. In any one or more aspects, the isomerization unit can be operated at a temperature in the range of less than 350°, for example about 20° C. to about 200° C.

First claim

We claim:

1. A process for removing p-xylene from a feed stream, comprising the steps of:
a) providing a feed stream including a mixture of xylene isomers, wherein the mixture includes at least p-xylene;
b) extracting p-xylene from the feed stream using an extractor to produce a p-xylene rich stream and a p-xylene deprived stream;
c) delivering the p-xylene deprived stream to an isomerization unit including an acidic sulfonated catalytic membrane, wherein the membrane includes Nafion-H and is used in an pervaporation process to produce an isomerized product including a higher proportion of p-xylene than in the p-xylene deprived stream delivered to the isomerization unit; and
d) admixing the isomerized product with the feed stream for delivery to the extractor.

2. The process of claim 1 , wherein the isomerization unit is operated at a temperature in the range of about 20° C. to about 200° C.

3. The process of claim 1 , wherein the feed stream further includes aromatics used to isolate xylenes.

4. The process of claim 3 , wherein the feed stream includes one or more of catalytically reformed naphthas, aromatics from a stream reforming process, and aromatics from biomass refineries.

5. The process of claim 1 , wherein the isomerization unit is a catalytic membrane reactor.

6. The process of claim 1 , wherein the isomerization unit is operated at a temperature in the range of about 70° C. to about 80° C.

7. A process for isomerizing a feed mixture including xylenes, the process comprising:
contacting the feed mixture with an acidic sulfonated catalytic membrane including Nafion-H at isomerization conditions in an isomerization zone, wherein a pervaporation process using the membrane is carried out within the isomerization zone; and
producing an isomerized product including a higher proportion of p-xylene than in the feed mixture.

8. The process of claim 7 , wherein the isomerization zone is operated at a temperature in the range of about 20° C. to about 200° C.

9. The process of claim 7 , wherein the feed stream includes aromatics used to isolate xylenes.

10. The process of claim 9 , wherein the feed stream includes one or more of catalytically reformed naphthas, aromatics from a stream reforming process, and aromatics from biomass refineries.

11. The process of claim 7 , wherein the isomerization zone is located within a catalytic membrane reactor.

12. A process for isomerizing a feed mixture including xylenes, comprising:
contacting the feed mixture with a catalyst at isomerization conditions in an isomerization zone to produce an isomerized product including a higher proportion of p-xylene than in the feed mixture, wherein the catalyst includes a superacidic sulfonated ionomeric membrane including Nafion-H, wherein the isomerization unit is operated at a temperature in the range of about 70° C. to about 80° C.

13. The process of claim 12 , wherein the feed mixture further includes aromatics used to isolate xylenes.

14. The process of claim 12 , wherein the feed mixture further includes one or more of catalytically reformed naphthas, aromatics from a steam reforming process, and aromatics from biomass refineries.

Assignees

• Univ King Abdullah Sci & Tech

Inventors

• Bilaus Rakan Sulaiman
• Pinnau Ingo

Classifications

• C07C15/08

  Xylenes · CPC title

• B01J19/2475

  Membrane reactors · CPC title

• B01J35/065

  Operations & Transport · mapped topic

• C07C5/2797

  with ion-exchange resins · CPC title

• B01J31/10

  sulfonated · CPC title